Brake units of said type are very widely used and have a container for working fluid, which container is inserted with a connector piece into a receiving bore in a master brake cylinder, in particular a tandem master brake cylinder or in a separate connector line, and is sealed off or even fixed by means of an elastic sealing element.
The initial filling of brake systems with working fluid is normally performed in automated fashion under high fill pressures (often >6 bar). Said pressure can result in leakages because the sealing element deforms or is forced out of its intended seat.
To prevent this, it is for example known for the sealing element to be equipped with radially encircling collars which engage into an encircling groove in the side wall of the receiving bore (or vice versa) and thus form an undercut which counteracts the axial displacement of the sealing element.
Production of such solutions is however complex and expensive. The installation process is also susceptible to errors because the undercut opposes straightforward handling during the installation process, and correct positioning of the collar in the groove must be ensured and checked.